Paper machine headbox

ABSTRACT

A paper machine headbox provided with an inlet for the pulp, rear and sidewalls, a bottom, a vertically and horizontally adjustable front wall, which together with the bottom constitutes an outlet slice portion having an invariable acute angle Alpha , means attached to the sidewalls of the headbox and the front wall for vertical and horizontal adjustment of the front wall, a mixing roller in close proximity to the slice portion and rotatably supported by slides horizontally movable along guides attached to the sidewalls of the headbox. In order to maintain the front wall and the mixing roller stationary in relation to each other when the front wall and the mixing roller are transferred in a direction parallel to the bottom and to maintain the distance of the mixing roller from the bottom and the front wall unchanged when the front wall is transferred in a direction perpendicular to the bottom a rigid connecting rod is mounted on both sides of the headbox. The lower end of the rod is pivotably attached to the slide on the same side of the headbox and the upper end of which is pivotably attached to the front wall, and the part of the front wall closest to the mixing roller being curved, the center point of the curving radius coinciding with the pivot of the upper end of the rods.

United States Patent 72] Inventor Toivo Johannes Niskanen llamina, Finland [21] Appl. No. 45,672

[22] Filed June 12, 1970 [45] Patented Jan. 11, 1972 [73] Assignee A. Ahlstrom Asakeyhtio Noornarkku, Finland [32] Priority June 23, 1969 [33] Finland [54] PAPER MACHINE HEADBOX 1 Claim, 2 Drawing Figs.

[52] HS. Cl 162/342, 162/344 [51] Int. Cl D211 1/18 [50] Field of Search 162/342, 346, 347, 344

[56] References Cited UNITED STATES PATENTS 2,744,452 5/1956 Niks 162/342 2,750,854 6/1956 McArn 162/342 Primary Examiner-Arthur D. Kellogg Attorney- Albert M. Parker ABSTRACT: A paper machine headbox provided with an inlet for the pulp, rear and sidewalls, a bottom, a vertically and horizontally adjustable front wall, which together with the bottom constitutes an outlet slice portion having an invariable acute angle a, means attached to the sidewalls of the headbox and the front wall for vertical and horizontal adjustment of the front wall, a mixing roller in close proximity to the slice portion and rotatably supported by slides horizontally movable along guides attached to the sidewalls of the headbox. In order to maintain the front wall and the mixing roller stationary in relation to each other when the front wall and the mixing roller are transferred in a direction parallel to the bottom and to maintain the distance of the mixing roller from the bottom and the front wall unchanged when the front wall is transferred in a direction perpendicular to the bottom a rigid connecting rod is mounted on both sides of the headbox. The lower end of the rod is pivotably attached to the slide on the same side of the headbox and the upper end of which is pivotably attached to the front wall, and the part of the front wall closest to the mixing roller being curved, the center point of the curving radius coinciding with the pivot of the upper end of the rods.

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PAPER MACHINE HEAIDBOX BACKGROUND OF THE INVENTION 1. Field of the invention The invention relates to the field of paper machine headboxes.

2. Prior Art in paper machines it has proven most practical to construct the lip portion of the headbox so that the upper lip can be adjusted both in the horizontal and in the vertical direction. This can be achieved by moving the upper lip and/or the front wall to which the upper lip is attached. The result of the transfer of the front wall of the headbox is that its distance from the mixing roller close to it is changed. On the other hand, considering the effectiveness of the mixing roller, it is important that the gap between the mantle of the mixing roller and the front wall remains small and unchanged. Different methods have been used to meet this requirement. 0f the known solutions we can mention, for example, the one introduced in the U.S. Pat. No. 2,750,854 and in which the movable part of the front wall can be turned so that its distance from the mixing roller stays practically constant when the lip angle changes. In a structure like this it is difficult, for example, to obtain an effective sealing between the stationary and the moving part. The sealing point is located below the liquid level, where the surfaces should be as even as possible so that fiber could not pile anywhere, and in this case an inconvenient projection is formed there. In addition the changing of the inclination of the front wall or the lap angle is a disadvantage with a harmful effect because the stock will flow to the wire at a different angle depending on the size of the lip opening or slice portion.

In addition solutions are known in which the mixing roller can be moved, directed by a slide or an eccentric device. in both cases the desired result that is, the distance of the apertured roller from both the front wall and the bottom plate remains unchangedis obtained only approximately. Another characteristic disadvantage of these solutions is that the roller does not follow the movement of the front wall but has to be adjusted separately.

it is also known a mechanical, electrical and pneumatic solution; in the mechanical structure the front wall and the mixing roller have been attached to each other with a geared wheel and geared rod. This solution, is however, relatively complex and not economical.

SUMMARY OF THE INVENTION According to the invention the front wall and the mixing roller have been attached to each other with two rigid connecting rods pivoted at both ends. Thus, when the front wall is moved in a direction parallel to the bottom, the position of the mixing roller does not change in relation to the front wall. When the front wall is moved in a direction perpendicular to the bottom, the mixing roller moves along the curving part of the front wall and parallel to the bottom, at which time its position in relation to the front wall changes, but the gaps between both the front wall and the roller and between the bottom and the roller remain unchanged.

According to the invention there is produced a simple adjustable front wall and mixing roller structure for headboxes, a structure in which the roller follows the movement of the front wall so that its distance from the front wall and the bottom plate stays unchanged.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically a longitudinal section of the structural principle of the headbox according to the invention; and

FIG. 2 shows schematically a side view of the lip part of a headbox according to the invention, equipped with a device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows the structural principle of the headbox in question. Part 1 is an adjustable front wall and 3 and immovable front wall. Part 2 is the mixing roller and 4 the bottom plate of the box. The angle a between the front wall and the bottom plate is the lip angle. Also, 5 is the sealing part, which follows the movement parallel to the bottom plate of the adjustable front wall.

In FIG. 2, the adjustable front wall I is attached to the mixing roller with a rigid connecting rod 6, the upper end of which is attached with bearings to the side of the upper part of the front wall 1 and the lower end of which is attached with bearings to a slide 7, which is directed, with the help of rails 8 to move in a direction parallel to the bottom plate 4 of the headbox. The mixing roller 2 has also been attached to the slide 7 with roller bearings.

As can be seen from FIG. 2, the part of the front wall I closest to the mixing roller 2 has been curved, the curving radius being R, the center point of which is at the pivot of the upper end of the connecting rod 6. Thus the mixing roller stays at the same distance from the front wall 1, that is, from the curving part of the wall, when the front wall is elevated and lowered in order to increase and decrease the opening of the lip or slice portion, even if the connecting rod pivots around its upper end.

When the front wall 1 is moved in a direction parallel to the bottom plate 4, the connecting rod 6 does not turn around its upper or lower end, and the front wall 1 and the mixing roller 2 remain stationary in relation to each other, in which case the mixing roller 2 moves an equal distance as the front wall 1 in a direction parallel to the bottom 4. it is clear that the front wall 1 can also be moved simultaneously upor downward, frontor backward, in which case, however, the mixing roller 2 moves only forward or backward in a direction parallel to the bottom 4. it is clear that the front wall 1 can also be moved simultaneously upor downward, frontor backward, in which case, however, the mixing roller 2 moves only forward or backward in a direction parallel to the bottom 4.

The vertical and horizontal movement of the front wall 1 is obtained advantageously with the help of a device 9 which has two slides 10 and 12 attached transversely in relation to each other. The vertical slide 10 is directed to move vertically along the rails which are attached to the sideplate of the headbox (not shown), with the help of a driving device 11 which is attached to the same sideplate with the other end of its spindle fitted to the slide valve 10. The horizontal movement of the front wall is obtained with the help of a driving device 14 attached to the side of the front wall I. The other end of this driving device 14 is fitted to the horizontal slide 12. Rails, attached to the side of the front wall 1, have been fitted above and below this slide 12. Thus the horizontal movement of the front wall 1 is obtained by moving the front wall I in relation to the slide 12 with the help of the driving device 14, and the vertical movement of the front wall I is obtained by making the slide 10 slide with help of a driving device 11, along the rails attached to the sideplate of the headbox. By using both of the driving devices 11, l4simultaneously the front wall 1 can be moved also obliquely upor downward. The driving devices 11, 14 are either hand or motor powered.

It is also possible to operate with only one connecting rod or one side of the headbox although serious difficulties will be encountered in such a modification.

What is claimed is:

1. Improvement in a paper machine headbox of the type having an inlet for the pulp, rear and sidewalls, a bottom, a vertically and horizontally adjustable front wall, which together with the bottom constitutes an outletslice portion having an invariable acute angle a, means attached to the sidewalls of the headbox and the front wall for vertical and horizontal adjustment of the front wall, a mixing roller in close proximity to the slice portion and rotatably supported by slides horizontally movable along guides attached to the sidewalls of the headbox, the improvement comprising:

other when the front wall and the mixing roller are transferred in a direction parallel to the bottom and to maintain the distance of the mixing roller from the bottom and the front wall unchanged when the front wall is transferred in a direction perpendicular to the bottom, whereby the mixing roller moves in relation to the front wall along the curved part thereof. 

1. Improvement in a paper machine headbox of the type having an inlet for the pulp, rear and sidewalls, a bottom, a vertically and horizontally adjustable front wall, which together with the bottom constitutes an outlet slice portion having an invariable acute angle Alpha , means attached to the sidewalls of the headbox and the front wall for vertical and horizontal adjustment of the front wall, a mixing roller in close proximity to the slice portion and rotatably supported by slides horizontally movable along guides attached to the sidewalls of the headbox, the improvement comprising: a rigid connecting rod on both sides of the headbox, the lower end of which is pivotably attached to the slide on the same side of the headbox and the upper end of which is pivotably attached to the front wall, and the part of the front wall closest to the mixing roller being curved, the center point of the curving radius coinciding with the pivot of the upper end of the rods to maintain the front wall and the mixing roller stationary in relation to each other when the front wall and the mixing roller are transferred in a direction parallel to the bottom and to maintain the distance of the mixing roller from the bottom and the front wall unchanged when the front wall is transferred in a direction perpendicular to the bottom, whereby the mixing roller moves in relation to the front wall along the curved part thereof. 